Effect: +50% Max HP at the cost of -50% HP Regen.
Unlock: Upgrade Regen Tome to Level 8
Leeching Crystal is a Rare item that trades HP Regen for Max HP. Each copy gives +50% Max HP while applying a x0.5 multiplier to your HP Regen stat. The first copy cuts your regen in half but gives a significant HP pool increase - a straightforward tradeoff that is usually worth taking if you have other healing sources.
Where it gets more complex is stacking. Each additional Leeching Crystal applies another x0.5 multiplier to HP Regen. At two copies, your HP Regen reaches zero. At three or more, it goes negative - you start losing HP over time instead of gaining it.
Leeching Crystal is also the prerequisite for unlocking Kevin. You need to find three Leeching Crystals in a single run to unlock Kevin for purchase.
The table below shows exactly how multiple copies affect HP Regen, based on a base HP Regen of 10. The multiplier compounds with each copy.
| Copies | HP Regen Multiplier | Base Regen (example: 10) | Actual Regen |
|---|---|---|---|
| 1 | x0.5 | 10 | 5 |
| 2 | x0 | 10 | 0 |
| 3 | x-0.5 | 10 | -5 (losing HP) |
| 4 | x-1 | 10 | -10 (losing HP) |
| 5 | x-1.5 | 10 | -15 (losing HP) |
Because the effect is a multiplier, increasing your HP Regen stat while in negative territory makes you lose HP faster, not slower. A Medkit that adds 45 HP Regen will scale the negative multiplier, meaning more HP loss per second. Once you have 3+ Leeching Crystals, HP Regen sources become harmful. The wiki confirms this explicitly.
Negative HP Regen from Leeching Crystal cannot kill you. It stops damaging you at 1 HP and does not affect shields. It also triggers on-damage item effects each tick, the same way enemy hits do.
Healing sources that still work with Leeching Crystal: Lifesteal (from any source), Borgar, Beacon, Demonic Blade, and Slurp Gloves. These are not affected by the HP Regen multiplier and heal normally regardless of how many Leeching Crystals you have.
Healing sources that stop working: Charge Shrine bonuses, HP Regen from Tomes, Medkit, Campfire, and Holy Book's HP Regen bonus. All of these are multiplied by the negative Regen multiplier and become counterproductive at 3+ copies. The wiki is explicit on this point.
At 3+ Leeching Crystals, the constant HP loss triggers on-damage items like Electric Plug, Golden Shield, and Coward's Cloak continuously without needing enemies to hit you. This creates a self-sustaining proc loop. Pair with Lifesteal to offset the HP drain and you get near-constant item activations for free.
| Property | Details |
|---|---|
| Unlock condition | Upgrade Regen Tome to Level 8 |
| Purchase | After unlocking, buy with Silver from Main Menu - Unlocks - Items |
| Rarity | Rare |
| Kevin unlock | Collect 3 Leeching Crystals in one run to also unlock Kevin |
Regen Tome is available from the start of the game. Reaching Level 8 requires consistent investment across multiple runs. Once unlocked, Leeching Crystal enters your loot pool as a Rare item and will appear with reasonable frequency from chests and the Shady Guy NPC.
Athena - Athena's Lock In passive increases damage at low HP. Leeching Crystal's +50% Max HP and reduced regen supports controlled low-HP play. Combine with Lifesteal to maintain that threshold and the damage bonus becomes consistent.
Megachad - Megachad's high base HP pool gets even larger with Leeching Crystal, making him even more durable. The regen tradeoff is manageable since Megachad's Flex ability absorbs incoming damage spikes.
Sir Chadwell - His Corrupted Sword weapon scales with difficulty, and the wiki notes Leeching Crystal can keep HP at 1 to maximize Corrupted Sword's low-HP damage bonus. A niche but documented interaction.
Each Leeching Crystal gives +50% Max HP at the cost of a x0.5 multiplier to HP Regen. One copy halves your regen. Two copies zeroes it out. Three or more copies turn it negative, meaning you lose HP over time. Negative HP Regen cannot kill you - it stops at 1 HP.
Upgrade Regen Tome to Level 8. After meeting that condition, go to Main Menu - Unlocks - Items and purchase Leeching Crystal with Silver to add it to your loot pool.
After purchasing it from the Unlocks menu, Leeching Crystal can appear from Treasure Chests and the Shady Guy NPC during runs. It is a Rare item, so it drops at a moderate rate - more common than Legendary items, less common than Default and Common items.
You need to find three Leeching Crystal drops in a single run to unlock Kevin. The best approach is to run Tier 3 where you have more stages and more chest opportunities, use the Shady Guy NPC whenever he appears, and have Luck-boosting items to improve your chances of rolling Rare items from chests. It may take several runs before you get three in one session.
